// SPDX-License-Identifier: GPL-2.0 #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifndef ETH_MAX_MTU #define ETH_MAX_MTU 0xFFFFU #endif #ifndef UDP_SEGMENT #define UDP_SEGMENT 103 #endif #ifndef UDP_MAX_SEGMENTS #define UDP_MAX_SEGMENTS (1 << 6UL) #endif #define CONST_MTU_TEST 1500 #define CONST_HDRLEN_V4 (sizeof(struct iphdr) + sizeof(struct udphdr)) #define CONST_HDRLEN_V6 (sizeof(struct ip6_hdr) + sizeof(struct udphdr)) #define CONST_MSS_V4 (CONST_MTU_TEST - CONST_HDRLEN_V4) #define CONST_MSS_V6 (CONST_MTU_TEST - CONST_HDRLEN_V6) #define CONST_MAX_SEGS_V4 (ETH_MAX_MTU / CONST_MSS_V4) #define CONST_MAX_SEGS_V6 (ETH_MAX_MTU / CONST_MSS_V6) static bool cfg_do_ipv4; static bool cfg_do_ipv6; static bool cfg_do_connected; static bool cfg_do_connectionless; static bool cfg_do_msgmore; static bool cfg_do_setsockopt; static int cfg_specific_test_id = -1; static const char cfg_ifname[] = "lo"; static unsigned short cfg_port = 9000; static char buf[ETH_MAX_MTU]; struct testcase { int tlen; /* send() buffer size, may exceed mss */ bool tfail; /* send() call is expected to fail */ int gso_len; /* mss after applying gso */ int r_num_mss; /* recv(): number of calls of full mss */ int r_len_last; /* recv(): size of last non-mss dgram, if any */ }; const struct in6_addr addr6 = IN6ADDR_LOOPBACK_INIT; const struct in_addr addr4 = { .s_addr = __constant_htonl(INADDR_LOOPBACK + 2) }; struct testcase testcases_v4[] = { { /* no GSO: send a single byte */ .tlen = 1, .r_len_last = 1, }, { /* no GSO: send a single MSS */ .tlen = CONST_MSS_V4, .r_num_mss = 1, }, { /* no GSO: send a single MSS + 1B: fail */ .tlen = CONST_MSS_V4 + 1, .tfail = true, }, { /* send a single MSS: will fall back to no GSO */ .tlen = CONST_MSS_V4, .gso_len = CONST_MSS_V4, .r_num_mss = 1, }, { /* send a single MSS + 1B */ .tlen = CONST_MSS_V4 + 1, .gso_len = CONST_MSS_V4, .r_num_mss = 1, .r_len_last = 1, }, { /* send exactly 2 MSS */ .tlen = CONST_MSS_V4 * 2, .gso_len = CONST_MSS_V4, .r_num_mss = 2, }, { /* send 2 MSS + 1B */ .tlen = (CONST_MSS_V4 * 2) + 1, .gso_len = CONST_MSS_V4, .r_num_mss = 2, .r_len_last = 1, }, { /* send MAX segs */ .tlen = (ETH_MAX_MTU / CONST_MSS_V4) * CONST_MSS_V4, .gso_len = CONST_MSS_V4, .r_num_mss = (ETH_MAX_MTU / CONST_MSS_V4), }, { /* send MAX bytes */ .tlen = ETH_MAX_MTU - CONST_HDRLEN_V4, .gso_len = CONST_MSS_V4, .r_num_mss = CONST_MAX_SEGS_V4, .r_len_last = ETH_MAX_MTU - CONST_HDRLEN_V4 - (CONST_MAX_SEGS_V4 * CONST_MSS_V4), }, { /* send MAX + 1: fail */ .tlen = ETH_MAX_MTU - CONST_HDRLEN_V4 + 1, .gso_len = CONST_MSS_V4, .tfail = true, }, { /* send a single 1B MSS: will fall back to no GSO */ .tlen = 1, .gso_len = 1, .r_num_mss = 1, }, { /* send 2 1B segments */ .tlen = 2, .gso_len = 1, .r_num_mss = 2, }, { /* send 2B + 2B + 1B segments */ .tlen = 5, .gso_len = 2, .r_num_mss = 2, .r_len_last = 1, }, { /* send max number of min sized segments */ .tlen = UDP_MAX_SEGMENTS, .gso_len = 1, .r_num_mss = UDP_MAX_SEGMENTS, }, { /* send max number + 1 of min sized segments: fail */ .tlen = UDP_MAX_SEGMENTS + 1, .gso_len = 1, .tfail = true, }, { /* EOL */ } }; #ifndef IP6_MAX_MTU #define IP6_MAX_MTU (ETH_MAX_MTU + sizeof(struct ip6_hdr)) #endif struct testcase testcases_v6[] = { { /* no GSO: send a single byte */ .tlen = 1, .r_len_last = 1, }, { /* no GSO: send a single MSS */ .tlen = CONST_MSS_V6, .r_num_mss = 1, }, { /* no GSO: send a single MSS + 1B: fail */ .tlen = CONST_MSS_V6 + 1, .tfail = true, }, { /* send a single MSS: will fall back to no GSO */ .tlen = CONST_MSS_V6, .gso_len = CONST_MSS_V6, .r_num_mss = 1, }, { /* send a single MSS + 1B */ .tlen = CONST_MSS_V6 + 1, .gso_len = CONST_MSS_V6, .r_num_mss = 1, .r_len_last = 1, }, { /* send exactly 2 MSS */ .tlen = CONST_MSS_V6 * 2, .gso_len = CONST_MSS_V6, .r_num_mss = 2, }, { /* send 2 MSS + 1B */ .tlen = (CONST_MSS_V6 * 2) + 1, .gso_len = CONST_MSS_V6, .r_num_mss = 2, .r_len_last = 1, }, { /* send MAX segs */ .tlen = (IP6_MAX_MTU / CONST_MSS_V6) * CONST_MSS_V6, .gso_len = CONST_MSS_V6, .r_num_mss = (IP6_MAX_MTU / CONST_MSS_V6), }, { /* send MAX bytes */ .tlen = IP6_MAX_MTU - CONST_HDRLEN_V6, .gso_len = CONST_MSS_V6, .r_num_mss = CONST_MAX_SEGS_V6, .r_len_last = IP6_MAX_MTU - CONST_HDRLEN_V6 - (CONST_MAX_SEGS_V6 * CONST_MSS_V6), }, { /* send MAX + 1: fail */ .tlen = IP6_MAX_MTU - CONST_HDRLEN_V6 + 1, .gso_len = CONST_MSS_V6, .tfail = true, }, { /* send a single 1B MSS: will fall back to no GSO */ .tlen = 1, .gso_len = 1, .r_num_mss = 1, }, { /* send 2 1B segments */ .tlen = 2, .gso_len = 1, .r_num_mss = 2, }, { /* send 2B + 2B + 1B segments */ .tlen = 5, .gso_len = 2, .r_num_mss = 2, .r_len_last = 1, }, { /* send max number of min sized segments */ .tlen = UDP_MAX_SEGMENTS, .gso_len = 1, .r_num_mss = UDP_MAX_SEGMENTS, }, { /* send max number + 1 of min sized segments: fail */ .tlen = UDP_MAX_SEGMENTS + 1, .gso_len = 1, .tfail = true, }, { /* EOL */ } }; static unsigned int get_device_mtu(int fd, const char *ifname) { struct ifreq ifr; memset(&ifr, 0, sizeof(ifr)); strcpy(ifr.ifr_name, ifname); if (ioctl(fd, SIOCGIFMTU, &ifr)) error(1, errno, "ioctl get mtu"); return ifr.ifr_mtu; } static void __set_device_mtu(int fd, const char *ifname, unsigned int mtu) { struct ifreq ifr; memset(&ifr, 0, sizeof(ifr)); ifr.ifr_mtu = mtu; strcpy(ifr.ifr_name, ifname); if (ioctl(fd, SIOCSIFMTU, &ifr)) error(1, errno, "ioctl set mtu"); } static void set_device_mtu(int fd, int mtu) { int val; val = get_device_mtu(fd, cfg_ifname); fprintf(stderr, "device mtu (orig): %u\n", val); __set_device_mtu(fd, cfg_ifname, mtu); val = get_device_mtu(fd, cfg_ifname); if (val != mtu) error(1, 0, "unable to set device mtu to %u\n", val); fprintf(stderr, "device mtu (test): %u\n", val); } static void set_pmtu_discover(int fd, bool is_ipv4) { int level, name, val; if (is_ipv4) { level = SOL_IP; name = IP_MTU_DISCOVER; val = IP_PMTUDISC_DO; } else { level = SOL_IPV6; name = IPV6_MTU_DISCOVER; val = IPV6_PMTUDISC_DO; } if (setsockopt(fd, level, name, &val, sizeof(val))) error(1, errno, "setsockopt path mtu"); } static unsigned int get_path_mtu(int fd, bool is_ipv4) { socklen_t vallen; unsigned int mtu; int ret; vallen = sizeof(mtu); if (is_ipv4) ret = getsockopt(fd, SOL_IP, IP_MTU, &mtu, &vallen); else ret = getsockopt(fd, SOL_IPV6, IPV6_MTU, &mtu, &vallen); if (ret) error(1, errno, "getsockopt mtu"); fprintf(stderr, "path mtu (read): %u\n", mtu); return mtu; } /* very wordy version of system("ip route add dev lo mtu 1500 127.0.0.3/32") */ static void set_route_mtu(int mtu, bool is_ipv4) { struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK }; struct nlmsghdr *nh; struct rtattr *rta; struct rtmsg *rt; char data[NLMSG_ALIGN(sizeof(*nh)) + NLMSG_ALIGN(sizeof(*rt)) + NLMSG_ALIGN(RTA_LENGTH(sizeof(addr6))) + NLMSG_ALIGN(RTA_LENGTH(sizeof(int))) + NLMSG_ALIGN(RTA_LENGTH(0) + RTA_LENGTH(sizeof(int)))]; int fd, ret, alen, off = 0; alen = is_ipv4 ? sizeof(addr4) : sizeof(addr6); fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE); if (fd == -1) error(1, errno, "socket netlink"); memset(data, 0, sizeof(data)); nh = (void *)data; nh->nlmsg_type = RTM_NEWROUTE; nh->nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE; off += NLMSG_ALIGN(sizeof(*nh)); rt = (void *)(data + off); rt->rtm_family = is_ipv4 ? AF_INET : AF_INET6; rt->rtm_table = RT_TABLE_MAIN; rt->rtm_dst_len = alen << 3; rt->rtm_protocol = RTPROT_BOOT; rt->rtm_scope = RT_SCOPE_UNIVERSE; rt->rtm_type = RTN_UNICAST; off += NLMSG_ALIGN(sizeof(*rt)); rta = (void *)(data + off); rta->rta_type = RTA_DST; rta->rta_len = RTA_LENGTH(alen); if (is_ipv4) memcpy(RTA_DATA(rta), &addr4, alen); else memcpy(RTA_DATA(rta), &addr6, alen); off += NLMSG_ALIGN(rta->rta_len); rta = (void *)(data + off); rta->rta_type = RTA_OIF; rta->rta_len = RTA_LENGTH(sizeof(int)); *((int *)(RTA_DATA(rta))) = 1; //if_nametoindex("lo"); off += NLMSG_ALIGN(rta->rta_len); /* MTU is a subtype in a metrics type */ rta = (void *)(data + off); rta->rta_type = RTA_METRICS; rta->rta_len = RTA_LENGTH(0) + RTA_LENGTH(sizeof(int)); off += NLMSG_ALIGN(rta->rta_len); /* now fill MTU subtype. Note that it fits within above rta_len */ rta = (void *)(((char *) rta) + RTA_LENGTH(0)); rta->rta_type = RTAX_MTU; rta->rta_len = RTA_LENGTH(sizeof(int)); *((int *)(RTA_DATA(rta))) = mtu; nh->nlmsg_len = off; ret = sendto(fd, data, off, 0, (void *)&nladdr, sizeof(nladdr)); if (ret != off) error(1, errno, "send netlink: %uB != %uB\n", ret, off); if (close(fd)) error(1, errno, "close netlink"); fprintf(stderr, "route mtu (test): %u\n", mtu); } static bool __send_one(int fd, struct msghdr *msg, int flags) { int ret; ret = sendmsg(fd, msg, flags); if (ret == -1 && (errno == EMSGSIZE || errno == ENOMEM || errno == EINVAL)) return false; if (ret == -1) error(1, errno, "sendmsg"); if (ret != msg->msg_iov->iov_len) error(1, 0, "sendto: %d != %lu", ret, msg->msg_iov->iov_len); if (msg->msg_flags) error(1, 0, "sendmsg: return flags 0x%x\n", msg->msg_flags); return true; } static bool send_one(int fd, int len, int gso_len, struct sockaddr *addr, socklen_t alen) { char control[CMSG_SPACE(sizeof(uint16_t))] = {0}; struct msghdr msg = {0}; struct iovec iov = {0}; struct cmsghdr *cm; iov.iov_base = buf; iov.iov_len = len; msg.msg_iov = &iov; msg.msg_iovlen = 1; msg.msg_name = addr; msg.msg_namelen = alen; if (gso_len && !cfg_do_setsockopt) { msg.msg_control = control; msg.msg_controllen = sizeof(control); cm = CMSG_FIRSTHDR(&msg); cm->cmsg_level = SOL_UDP; cm->cmsg_type = UDP_SEGMENT; cm->cmsg_len = CMSG_LEN(sizeof(uint16_t)); *((uint16_t *) CMSG_DATA(cm)) = gso_len; } /* If MSG_MORE, send 1 byte followed by remainder */ if (cfg_do_msgmore && len > 1) { iov.iov_len = 1; if (!__send_one(fd, &msg, MSG_MORE)) error(1, 0, "send 1B failed"); iov.iov_base++; iov.iov_len = len - 1; } return __send_one(fd, &msg, 0); } static int recv_one(int fd, int flags) { int ret; ret = recv(fd, buf, sizeof(buf), flags); if (ret == -1 && errno == EAGAIN && (flags & MSG_DONTWAIT)) return 0; if (ret == -1) error(1, errno, "recv"); return ret; } static void run_one(struct testcase *test, int fdt, int fdr, struct sockaddr *addr, socklen_t alen) { int i, ret, val, mss; bool sent; fprintf(stderr, "ipv%d tx:%d gso:%d %s\n", addr->sa_family == AF_INET ? 4 : 6, test->tlen, test->gso_len, test->tfail ? "(fail)" : ""); val = test->gso_len; if (cfg_do_setsockopt) { if (setsockopt(fdt, SOL_UDP, UDP_SEGMENT, &val, sizeof(val))) error(1, errno, "setsockopt udp segment"); } sent = send_one(fdt, test->tlen, test->gso_len, addr, alen); if (sent && test->tfail) error(1, 0, "send succeeded while expecting failure"); if (!sent && !test->tfail) error(1, 0, "send failed while expecting success"); if (!sent) return; if (test->gso_len) mss = test->gso_len; else mss = addr->sa_family == AF_INET ? CONST_MSS_V4 : CONST_MSS_V6; /* Recv all full MSS datagrams */ for (i = 0; i < test->r_num_mss; i++) { ret = recv_one(fdr, 0); if (ret != mss) error(1, 0, "recv.%d: %d != %d", i, ret, mss); } /* Recv the non-full last datagram, if tlen was not a multiple of mss */ if (test->r_len_last) { ret = recv_one(fdr, 0); if (ret != test->r_len_last) error(1, 0, "recv.%d: %d != %d (last)", i, ret, test->r_len_last); } /* Verify received all data */ ret = recv_one(fdr, MSG_DONTWAIT); if (ret) error(1, 0, "recv: unexpected datagram"); } static void run_all(int fdt, int fdr, struct sockaddr *addr, socklen_t alen) { struct testcase *tests, *test; tests = addr->sa_family == AF_INET ? testcases_v4 : testcases_v6; for (test = tests; test->tlen; test++) { /* if a specific test is given, then skip all others */ if (cfg_specific_test_id == -1 || cfg_specific_test_id == test - tests) run_one(test, fdt, fdr, addr, alen); } } static void run_test(struct sockaddr *addr, socklen_t alen) { struct timeval tv = { .tv_usec = 100 * 1000 }; int fdr, fdt, val; fdr = socket(addr->sa_family, SOCK_DGRAM, 0); if (fdr == -1) error(1, errno, "socket r"); if (bind(fdr, addr, alen)) error(1, errno, "bind"); /* Have tests fail quickly instead of hang */ if (setsockopt(fdr, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv))) error(1, errno, "setsockopt rcv timeout"); fdt = socket(addr->sa_family, SOCK_DGRAM, 0); if (fdt == -1) error(1, errno, "socket t"); /* Do not fragment these datagrams: only succeed if GSO works */ set_pmtu_discover(fdt, addr->sa_family == AF_INET); if (cfg_do_connectionless) { set_device_mtu(fdt, CONST_MTU_TEST); run_all(fdt, fdr, addr, alen); } if (cfg_do_connected) { set_device_mtu(fdt, CONST_MTU_TEST + 100); set_route_mtu(CONST_MTU_TEST, addr->sa_family == AF_INET); if (connect(fdt, addr, alen)) error(1, errno, "connect"); val = get_path_mtu(fdt, addr->sa_family == AF_INET); if (val != CONST_MTU_TEST) error(1, 0, "bad path mtu %u\n", val); run_all(fdt, fdr, addr, 0 /* use connected addr */); } if (close(fdt)) error(1, errno, "close t"); if (close(fdr)) error(1, errno, "close r"); } static void run_test_v4(void) { struct sockaddr_in addr = {0}; addr.sin_family = AF_INET; addr.sin_port = htons(cfg_port); addr.sin_addr = addr4; run_test((void *)&addr, sizeof(addr)); } static void run_test_v6(void) { struct sockaddr_in6 addr = {0}; addr.sin6_family = AF_INET6; addr.sin6_port = htons(cfg_port); addr.sin6_addr = addr6; run_test((void *)&addr, sizeof(addr)); } static void parse_opts(int argc, char **argv) { int c; while ((c = getopt(argc, argv, "46cCmst:")) != -1) { switch (c) { case '4': cfg_do_ipv4 = true; break; case '6': cfg_do_ipv6 = true; break; case 'c': cfg_do_connected = true; break; case 'C': cfg_do_connectionless = true; break; case 'm': cfg_do_msgmore = true; break; case 's': cfg_do_setsockopt = true; break; case 't': cfg_specific_test_id = strtoul(optarg, NULL, 0); break; default: error(1, 0, "%s: parse error", argv[0]); } } } int main(int argc, char **argv) { parse_opts(argc, argv); if (cfg_do_ipv4) run_test_v4(); if (cfg_do_ipv6) run_test_v6(); fprintf(stderr, "OK\n"); return 0; }